1. Field of the Invention
This invention relates to railroad car couplers and more particularly to couplers having the Type-E coupler head.
2. Prior Art
Railroad car couplers having a Type-E or Type-F coupler head are in common use today. Each coupler head type has been approved by the AAR (Association of American Railroads) wherein the couplers are assembled from standard components. The use of standard components allows the railroads to purchase couplers and related replacement parts from several manufacturers with assurance that such parts can be used interchangeably.
The standard Type-E coupler is disclosed in detail in U.S. Pat. Nos. 3,850,312 and 3,853,228, for example. The 3,850,312 patent suggests the use of an extended lockset seat on the lock of the coupler which relocates a center of gravity of the lock to improve lock rotation. The 3,853,228 patent discloses an improvement to the E-type coupler operation obtained by restricting movement of the knuckle thrower. Additionally, the 1974 Edition of Car and Locomotive Cyclopedia of American Practices, compiled and edited for the AAR by Simmons-Boardman Publishing Corporation, New York, N.Y., is an excellent source of detailed information on the AAR standard couplers and related nomenclature.
In spite of its long and continuous use, the Type-E coupler is not free of operating problems. For example, when the coupler head lock is placed in its lockset position, the knuckle may fail to open to release a second coupler mated thereto. This failure in operation can create a dangerous condition since the unreleased knuckle may transfer draft forces to cause movement of its respective railroad car or a further car to which that car is joined.